Using pyinstaller with .ui GUI files - No such file or directory error

[snippsat]

Add this,then it should work.

from PyQt5 import QtWidgets, uic
import sys, os

if getattr(sys, 'frozen', False):
    os.chdir(sys._MEIPASS)

class HelloApp(object):
    def __init__(self, app):
        self.app = app
        self.ui = uic.loadUi('helloGUI.ui')
        self.ui.show()
        self.run()

    def run(self):
        self.app.exec_()

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    HelloApp(app)

In many cases for lager prosje is better to use --onedir,then do not need to fix _MEIPASS(the path that a single .exe will use)

pyinstaller --clean --windowed --onedir --add-data helloGUI.ui;. qt_code.py

Then later can eg pack it with eg Inno Setup then get single setup.exe which has a installer.
Or can just .zip to one file,and share that.
It depend one use case a singe .exe is easy to share a,but many will not a run a executable .exe if not sure what is.
A installer(that also has a uninstaller) also make some Doc,is the professional looking way if want to share in a larger scale.